package org.vsg.common.biz.uid;

import java.net.InetAddress;
import java.rmi.server.UID;
import java.security.SecureRandom;

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * 
 * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
 * 
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License. You can obtain
 * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
 * or glassfish/bootstrap/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 * 
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
 * Sun designates this particular file as subject to the "Classpath" exception
 * as provided by Sun in the GPL Version 2 section of the License file that
 * accompanied this code.  If applicable, add the following below the License
 * Header, with the fields enclosed by brackets [] replaced by your own
 * identifying information: "Portions Copyrighted [year]
 * [name of copyright owner]"
 * 
 * Contributor(s):
 * 
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 */
public class UuidUtil {

	  static final String _inetAddr = initInetAddr();

	  // first method (from MarketMaker Guid)
	  public static String generateUuidMM() {
	    return new StringBuffer(new UID().toString()).reverse().append(':').append(_inetAddr)
	        .toString();
	  }

	  // second method
	  public static String generateUuid() {
	    return generateUuid(new Object());
	  }

	  // this method can take in the session object
	  // and insure better uniqueness guarantees
	  public static String generateUuid(Object obj) {

	    // low order time bits
	    long presentTime = System.currentTimeMillis();
	    int presentTimeLow = (int) presentTime & 0xFFFFFFFF;
	    String presentTimeStringLow = formatHexString(presentTimeLow);

	    StringBuffer sb = new StringBuffer(50);
	    sb.append(presentTimeStringLow);
	    // sb.append(":");
	    sb.append(getIdentityHashCode(obj));
	    // sb.append(":");
	    // sb.append(_inetAddr);
	    sb.append(addRandomTo(_inetAddr));
	    // sb.append(":");
	    sb.append(getNextRandomString());
	    return sb.toString();
	  }

	  /**
	   * Method initInetAddr
	   * 
	   * 
	   * @return
	   * 
	   * @audience
	   */
	  private static String initInetAddr() {

	    try {
	      byte[] bytes = InetAddress.getLocalHost().getAddress();
	      StringBuffer b = new StringBuffer();
	      String s = null;

	      for (int i = 0; i < bytes.length; i++) {
	        s = Integer.toHexString(bytes[i]);

	        if (bytes[i] < 0) {
	          b.append(s.substring(s.length() - 2));
	        } else {
	          b.append(s);
	        }
	      }

	      return b.toString();
	    } catch (Exception ex) {
	      // must return a value
	      return "a48eb993";
	      // return null;
	    }
	  }

	  private static String addRandomTo(String hexString) {
	    long hexAsLong = convertToLong(hexString);
	    int nextRandom = getNextInt();
	    long resultInt = hexAsLong + nextRandom;
	    String result = Long.toHexString(resultInt);
	    // START PWC 6425338
	    // Always return a length of 7
	    int len = result.length();
	    if (len < 7) {
	      result = padto7(result);
	    } else {
	      result = result.substring(len - 7, len);
	    }
	    // END PWC 6425338
	    return result;
	  }

	  /**
	   * Method getIdentityHashCode
	   * 
	   * 
	   * @return
	   * 
	   * @audience
	   */
	  private static String getIdentityHashCode(Object obj) {

	    String result = null;
	    try {
	      int hc = System.identityHashCode(obj);
	      return formatHexString(hc);

	    } catch (Exception ex) {
	      // must return a value
	      // return null;
	      return "8AF5182";
	    }
	  }

	  private static String formatHexString(int inputInt) {
	    String result = null;
	    String s = Integer.toHexString(inputInt);
	    /*
	     * PWC 6425338 if(s.length() < 8) { result = s; } else { result =
	     * s.substring(0, 7); }
	     */
	    // START PWC 6425338
	    // Always return a length of 7
	    int len = s.length();
	    if (len < 7) {
	      result = padto7(s);
	    } else {
	      result = s.substring(len - 7, len);
	    }
	    // END PWC 6425338
	    return result;
	  }

	  private static synchronized int getNextInt() {
	    return _seeder.nextInt();
	  }

	  private static String getNextRandomString() {
	    int nextInt = getNextInt();
	    return formatHexString(nextInt);
	  }

	  private static long convertToLong(String hexString) {
	    long result = 0;
	    try {
	      result = (Long.valueOf(hexString, 16)).longValue();
	    } catch (NumberFormatException ex) {
	    }
	    return result;
	  }

	  private static SecureRandom _seeder = new SecureRandom();
	
	  // START PWC 6425338
	  /*
	   * Pads the given string to a length of 7.
	   */
	  private static String padto7(String s) {

	    int i = 0;
	    char[] chars = new char[7];
	    int len = s.length();
	    while (i < len) {
	      chars[i] = s.charAt(i);
	      i++;
	    }
	    while (i < 7) {
	      chars[i++] = '0';
	    }
	    return new String(chars);
	  }
	  
}
